Apparatus for bending and forming tubing, rods, wires and the like



Jan. 16, 1962 P. KILHAM 3,016,943

APPARATUS FOR BENDING AND FORMING TUBING, RODS, WIRES AND THE} LIKE Filed Feb. 17, 1958 4 Sheets-Sheet 1 II II 1] I A up P. KILHAM APPARATUS FOR BENDING AND FORMING TUBING, RODS, WIRES AND THE LIKE Jan. 16, 1962 4 Sheets-Sheet 2 Filed Feb. 17, 1958 172 were tor,

Peter Kilizam,

96X 90 w AH.

Jan. 16, 1962 P KILHAM 3,016,943

APPARATUS FO BENDING AND FORMING TUBING, RODS, WIRES AND THE LIKE Peter K62 am,

3/ WW Q Jan. 16, 1962 p. KILHAM 3,016,943

APPARATUS FOR BENDING AND FORMING TUBING, RODS, WIRES AND THE LIKE 4 Sheets-Sheet 4 Filed Feb. 17, 1958 I 1 R376 I 3 IFZGG r352 [328 I 364 LON /6 1/ 20H- 280 282 342 .340 330 332 I [334 350 I 34a OFF 3/2 3/6 320 374 370 3/0 00 3/4 302 3/8 304 L 'L J J J'nventm; Peter ffz'lk m 5/ WW 3,016,943 APPARATUS FOR BENDING AND FORMING TUBING, RODS, WIRES AND THE LIKE Peter Kilharn, Plainville, Mass., assignor, by rnesne assignments, to Maclodyne Corporation, East Providence,

R.I., a corporation of Rhode Island Filed Feb. 17, 1958, Ser. No. 715,699 8 Claims. (Cl. 153-40) This invention relates to forming machines, and in particular to machines for forming elongated metal stock into arcuate shapes.

Among the several objects of the invention may be noted the provision of a forming or bending machine of the general class by means of which metal strip, tubing, or rod may be bent automatically into predetermined arcuate shapes; the provision of a machine of the class described by means of which arcuate bends may be formed in strip, tube or rod stock in such a way that the initial bend may be made close to the end of the stock; the provision of a machine of the general class described which utilizes rotating center and forming rolls, with the latter rotating automatically about the former; the provision of a machine of any of the above classes which is capable of bending thinwall tubing without crinkling the wall of the tubing along the inner radius of the bend, particularly at the start of a bending operation; and the provision of a machine of the general class specified above which is simple in principle, easy to adjust and operate, and economical to build and maintain. Other objects and advantages of the invention will be in part obvious and in part pointed out herein below.

The invention accordingly comprises the elements and combinations of elements, features of construction, and arrangement of parts which will be exempiified in the structures hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings, in which one of the various possible embodiments of the invention is illustrated:

FIG. 1 is a plan view of one embodiment of the invention;

FIG. 2 is a side sectional view of the FIG. 1 embodiment, taken in the direction of sight lines 2-2 on FIG 1, to show the interior construction;

FIG. 3 is a plan view of a portion of the FIG. 1, shown greatly enlarged in proportion to FIG. 1, to show in greater detail certain features of construction, and also showing certain operating parts in a second position;

FIG. 4 is a sectional view, taken in the direction of sight lines 4-4 on FIG. 3;

FIG. 5 is a sectional view of a detail of FIG. 4, taken in the direction of sight lines 5-5 thereon;

FIG. 6 is a vertical sectional view of a portion of FiG. 3, taken in the direction of sight lines 6-6 thereon;

FIG. 7 is a sectional view of a portion of FIG. 6, taken in the direction of sight lines 7-7 thereon;

FIG. 8 is a horizontal sectional view, shown partly in plan of a portion of FIG. 4, taken in the direction of sight lines 8-8 thereon, to show stock being bent in the embodiment; and

FIG. 9 is a schematic wiring diagram showing one possible set of electrical connections for the machine.

Similar reference characters indicate corresponding arts throughout the several views of the drawings.

There are and have been available prior machines for bending metal strip, tube and rod into arcuate shapes. However, in some instances these prior machines have been difiicult to adjust and operate; and in many instances it has been relatively difficult, if not impossible, to get a bend close to the end of the stock. Also, loadnited States Patent 0 7 3,016,943 Patented Jan. 16, 1952 ing the machine has been difficult, particularly when thin wall tubing has been the stock to be bent, since such tubing distorts out of shape fairly easily, particularly at the ends. In addition, in many instances it has been difiicult, if not impossible, to avoid wrinkling that part of the tube wall which becomes compressed (during a bending operation) along the inner radius of the arcuate shape. This is particularly true of tubing whose wall is thin compared to the diameter of the tube.

The present invention minimizes the above difliculties, and eliminates them in many instances. In addition, the machine and its principle of operation are essentially simple, thus leading to a construction which is readily adaptable to automatic or semi-automatic operation. A detailed description now follows:

Referring now to FIGS. 1 and 2, there is shown a stand, indicated generally by numeral 2, comprising a top plate 4-, two side plates 6 and 8, a front panel 10, a control panel 12, and a bottom plate 14. These panels are fabricated in any conventional way, and in the present instance were formed of sheet steel and bolted or welded together.

Installed on the panel 10 are the momentary-contact type of electrical pushbuttons, six in number, of which three are shown in FIG. 1 and numbered 16, 18 and 20.

On top plate 4 there are mounted the forming head, indicated generally by numeral 22; and a portion of the drive means for head 22, indicated generally by numeral 24. On bottom plate 14 there are mounted the rest of the drive means for the forming head, indicated generally by numeral 26; and an electromagnetic valve and relay assembly (indicated generally by numeral 28) for the control of the drive means and under the control of the said push-buttons.

Drive head 22 comprises the base 30, the upright support 32 and the overhanging arm 34. Support 32 is fastened to base 30 by means of machine screws or bolts 36 (see FIG. 4) and arm 34 is fastened to support 32 by means of machine screws or bolts 38.

The inner or free end of arm 34 is provided with a hole 40 into which is fitted the sleeve bearing 42 having a shoulder 44 overlying the arm 34 and providing a fiat upper bearing surface as well as the inner bearing surface. Base 30 is provided with a hole 46 into which is fitted one end of a hollow bearing stud 48. Stud 48 is provided with a shoulder 50 and threaded end 52. Base 30 is clamped, as shown, between shoulder 56 and clamping nut 54. Into the lower end of stud 48 is fitted the sleeve bearing 56 having shoulder 58 overlying the end of stud 48, and thus providing a flat lower bearing surface as well as the inner bearing surface. The location of holes 40 and 46 is such that when bearings 42 and 56 are fitted therein, these bearings are axially in alignment. (If desired, hole 46 can be made slightly over size, thus permitting, prior to clamping by nut 54, a slight lateral shifting of stud 48 to bring said bearings into alignment.)

Passing through and rotating in the bearings 42 and 56 is the drive shaft 60, whose purpose will be more fully explained below.

Surrounding drive shaft 66 is a rotating table assembly comprising an outer cylinder 62 and a table 64 attached thereto by screws 65. Table 54 is provided with a ringtype boss 68 as an integral part thereof which nicely fits the interior of cylinder 62 and thus locates the table on the cylinder. A pair of ball-bearings 70 and 72 support cylinder 62 on the stud 48 by having their inner and outer races engage, respectively, the stud 48 and the inner wall of cylinder 62. Concentric spacer rings 74 and 76 respectively slidably engage the stud 48 and the inner cylinder wall, to space the roller bearings apart asshown. The inner race 78 of ball bearing 72 rests against the top surface of shoulder 50, and a spring clip 80 (fitting into a suitably provided groove in stud 48) serves to hold the ball-bearings and spacers in longitudinal position on the stud 48. The outer races of the ball'bearings are preferably squeeze-fitted into cylinder 62, but if desired, other fastening means may be used.

Table 64 is provided with an upstanding neck 82 into which is fitted the sleeve bearing 84. Shaft 60 rotates freely in bearing 84.

The bottom end of cylinder 62 is provided with a shoulder 86, and onto this is squeeze fitted the sprocketwheel 88. Thus, turning the sprocket-wheel 88 will rotate the table assembly about the stud 48. As mentioned above, shaft 60 turns within stud 48, and thus shaft 60 and the table assembly are rotatable independently of each other.

Surmounting table 64 and lying thereon is the arm 90. (See FIGS. 1 and 3.) Arm 90 is provided with a clevis 92 at one end thereof, which engages the neck 82 and is clamped thereto by the bolt 94 in conventional manner. Thus, when table 64 is rotated by sprocket-wheel 88, arm 90 is rotated with the table.

Arm 90 is provided with a slot 96 therethrough, and a channel 98 wider than the slot is milled in the under side of arm 90. (See FIGS. 6 and 7.) Slidably mounted on the top of arm 90 is the forming-roll bearing block 100. Slidable in the channel 98 is the T-block 102 which is suitably threaded to receive the bolt 104 and the threaded stud 106. Bolt 104 is provided with a head 108, and stud 106 is provided wih a laterally extending shoulder 110, as shown, each of head 188 and shoulder 110 being preferably hexagon in shape so as to enable a Wrench to be applied to turn the bolt and stud to clamp the blocks 100 and 102 together against their respective bearing surfaces, thus anchoring the assembly longitudinally in the slot 96. By loosening the bolt and stud, the assembly can be adjusted in a desired position on arm 90.

Extending above shoulder 110 as an integral part thereof is the cylindrical neck which serves as a bearing shaft 112 for the form roll 114 and its driving gear 116, both of these rotating freely on. shaft 112, and the roll 114 being anchored to gear 116 by means of pins 118 which are fitted into suitably provided and aligned holes in the mating surfaces of the roll an gear. The form roll 114 iscounter-bored to receive the bolt 120, a suitable shoulder being provided against which the under side of bolt 120 may bear to anchor roll 114 and gear 116 on shaft 112 when bolt 121 is screwed into threaded hole 122 in shaft 112. Form roll 114 is provided with a circumferential groove 124 of proper size and shape to conform to the size and shape of the stock to be bent.

Arm 34 is also provided with a slot 126 extending there through. (See FIGS. 3, 4 and 5.) An elongated T-block 128 is inserted upwardly in slot 126 (see FIG. and is provided with threaded holes 130 and 132 therein. A bolt 134 screws into hole 130 and has washer 136 under its head, as shown. Tightening bolt 134 serves to clamp the T-block 128 longitudinally in place in arm 34. A stud 138 similar to stud 106 is threaded at one end toscrew into hole 132, and is provided with the laterally extending hexagonal shoulder 140, as well as the upwardly extending shaft 142. Turning. the stud 133 to tighten it also serves to anchor T-block 128 in place. Shaft 142 rotatably mounts form roll 144 and its drive gear 146, these being anchored together by the pins 148 which are fitted into suitably aligned holes in the mating surfaces of the roll and associated gear. Roll 144 is also counterbored to receive bolt suitable shoulders being provided to engage the under surface of the head of bolt 150, the bolt thus locking the gear and roll to shaft 142 when the bolt is screwed into a threaded hole provided in shaft 142. Roll 144 is provided with a circumferential groove 152 of propersize and shape to conform to the size and shape of the stock to be bent.

Shaft '60 is provided at its upper end with the reduced neck portion 154 which serves to mount the form roll 156. This roll is provided with a center bore 158 slidably fitting neck 154, and about its bottom periphery is provided with gear teeth 160. Shaft 60 is also provided at its upper end with the sidewise extending flat shoulder piece 162 which is made integral with the shaft so as to turn therewith. Aligned radial grooves 164 and 166 are provided, respectively, in the bottom surface of the roll 156 and top surface of the shoulder 162, and these receive the keys 163 and 170 so that gear 156 will be turned by shaft 60. Neck 154 is provided with the threaded hole 172 to receive the bolt 174 which by means of its head and washer 176 clamps roll 156 to the shoulder 162. Form roll 156 is provided with the circumferential groove 178 of proper size and shape to conform to the size and shape of the stock to be bent.

An oil hole 180 is drilled in the end of shaft 60, and cross-drilled oil feed holes 182 and 184 will permit oil to reach the sleeve bearings 40 and 84. Suitable indicia 186 are provided on table 64 to show the angular rotation of the table in use, and an index 188 may be mounted on support 32 for indicating purposes.

The teeth of each of gears 116 and 146 engage teeth 160 of form roll 156, so that as form roll 156 rotates, it causes each of form rolls 114 and 144 to rotate. Slight adjustments to have each peripheral groove fit against the stock snugly is provided by the aforementioned adjustments of the respective T-blocks. Also, if for purposes of obtaining different radii of bending in the selected stock, it is desired to change either the roll sizes or gear sizes, the aforementioned adjustability permits the necessary positioning of the respective form rolls.

It is to be noted that form rolls 114 and 144 and their respective gears 116 and 146 are of smaller diameter than form roll 156 and its respective gear 166 so that when driven, form rolls 114 and 144 have a greater surface speed than form roll 156.

The complete forming head 22 is fastened to top plate I 4 by means of bolts 190 which pass through holes in plate 4 and screw into suitably aligned tapped holes 192 in base 30. A hole 194 is provided in plate 4 to accommodate nut 54.

Referring now to FIGS. 1 and 2, there will now be described the drive means for table 64 and shaft 60.

For table 64, the drive means 24 comprises an air cylinder 200 which is fastened by one end 201 and by conventional means to an upright 202 in such manner as to extend horizontally along the top plate 4. Forward of the cylinder, a second upright 204- is fastened to top plate 4. By means of properly aligned bearing holes in uprights 202 and 204 on each side of cylinder 200, the threaded screw shafts 206 and 208 are rotatably mounted, suitable retaining collars 210 and 212 being provided to maintain the shafts in longitudinal correct position. The ends of the shafts project beyond upright 202, and to these ends are attached the pinions 214 and 216. A third pinion 218 is mounted on its own shaft (which is secured to upright 202 in conventional manner) and engages each of pinions 214 and 216. A crank 220 is attached to pinion 218 whereby the latter may be rotated to turn pinions 214 and 216 and thus shafts 206 and 208. As indicated above, each of these shafts is provided with a screwthread 222.

An adjustable cross-arm 224 spans the shafts 206 and 268 and is provided with suitably threaded holes 226 which are engaged by the screw threads 222. Thus as shafts 206 and 208 are rotated by means of crank 220, the cross-arm 224 is caused to move toward or away from the end 228 of cylinder 200.

The piston-rod 230 of the cylinder passes through a hole 232 provided in the cross-arm 224, and has at its end the clevis 234 and nut 236, the diameter of which is larger than the diameter of hole 232.

Attached by one end 238 to a support 240 on topplate 4 is a tension spring 242. To the other end 244 of the spring is attached one end of the sprocket chain 246.

Sprocket chain 246 engages the teeth of sprocket wheel 88, and its other end is fastened to clevis 234. In the position of the parts shown in FIGS. 1 and 2, the piston of the cylinder is at its furthest left position, and there is a slight tension in the spring, just enough to cause the spring to pull table 64 counter-clockwise to the position shown. Thus spring 242 is used to provide return motion to table 64.

When air is forced into cylinder 200 through inlet hose 248, the piston rod 230 moves to the right, thus drawing chain 246 with it against the bias of spring 242. As chain 246 is thus drawn, it rotates table 64 and arm 90. This motion continues until nut 236 strikes cross-arm 224, at which point the piston rod is stopped. By turning crank 20 and thus adjusting the position of cross-arm 224, the amount of motion of the chain and thus table 64 and arm 90 can be adjusted. When air is forced into cylinder via inlet hose 250, piston 230 moves to the left, and spring 242 retracts the chain to the FIG. 1 position.

Mounted below top plate 4 and on bottom plate 14 is the electromagnetic air-valve 28 which is of standard construction and is controlled electrically to admit air by hoses 248 and 250 on each side of the inner piston of the cylinder 24 in conventional manner. A hose 252 connects the valve to a source of compressed air.

Also mounted on plate 14 is the electric motor 254 which is connected by drive belt 256 to the speed reducing mechanism 258, the latter being of well-known construction. The reduced-speed, vertical shaft 260 of the gear-reducer 258 is connected directly to shaft 60 by means of a conventional flexible coupling 262.

Mounted either on panel or elsewhere where con venient and suitable within the apparatus are the two double-pole single-throw electromagnetic relays 264 and 266 each with its associated electrical contacts as follows: For relay 264, the stationary contacts 268 and 270, and the movable contact arms 272 and 274, each arm being electrically conducting. For relay 266, the stationary contacts 276 and 278, and the movable contact arms 230 and 282, each arm being electrically conducting. In conventional manner, when the coil of each relay is energized, the armature of the relay pulls the respective contact arms to the left (as drawn) to make certain electrical connections, each relay being biased so that these connections are open when the relay coils are not energized.

Push-buttons 16, 18, and 20 are of the momentary contact type and are normally biased in the contact-open position. Switch 16 has two sets of contacts which are closed when the push-button is pushed, namely, one set being contacts 284 and 286. The other set being contacts 288 and 290. Switches 18 and 20 each have one set of contacts, namely and respectively, contacts 292 and 294, and 296 and 298.

Push buttons 300, 302 and 304 are momentary contact switches (mounted on panel 12) and are normally biased in the contact closed position. Switch 300 has two sets of contacts which are opened when the pushbutton is pushed, namely, one set being contacts 306 and 308, the other set being contacts 310 and 312. Switches 302 and 304 each have one set of contacts, namely and respectively, contacts 314 and 316, and contacts 318 and 320.

The functions of the respective switches are as follows: Switch 16 actuates both relays 264 and 266 and thus motor 254 and air-valve 28; and switch 300 controls a lock-in circuit for both relays 264 and 266. Switch 18 actuates only relay 266 and thus only motor 254; switch 302 controls a lock-in circuit for only relay 266. Switch 20 actuates only relay 264 and thus only air-valve 28; switch 304 controls a lock-in circuit for only relay 264. The wiring connections between the respective switches, the motor, air-valve, and relays will be given in the explanation, now to follow, of the operation of the machine.

Referring now to FIGS. 3 and 8, in FIG. 3 the arm 90 is shown (in full lines) in the position it is in when stock 322 (here, tubing) is first loaded in the machine. The dotted-line position of arm shows an illustrative end position of the arm. In FIG. 8, the dotted-line position of arm 90 is the initial loading position, and the fullline position is that of the arm at an illustrative end position.

It will be noticed that in the loading position of arm 90, the positions of the form rolls 114, 144 and 156 are such that those portions of grooves 124 and 152 which are juxtaposed to groove 178 define, in essence, portions of an imaginary cylinder having a straight axis and which is approximately the same outside diameter of the stock 322 being inserted. For this reason, the stock may be relatively freely inserted between the grooves of the rolls, as shown in FIG. 3, without having to bend as it is loaded. This feature is a decided advantage and lends itself to quick loading of the machine. With the stock thus loaded, either of two operations may now be carried out.

First: if it is desired to move the stock along a straight line to preserve an unbent first portion, push-button 18 is momentarily actuated to close contacts 292 and 294. This energizes relay 266 as follows: From one side of power line 324 by wires 326 and 327 to the coil of relay 266, and thence by wires 329 and 328, contacts 294 and 292, wire 330, and wires 332 and 334 back to the other side of the power line. The armature of the relay pulls in, and conducts power to the motor 254 as follows: from one side of the power line by wire 326, contact arm 280, contact 276, wire 336, to motor 254, and thence by wire 338 back to the other side of the power line. At the same time, a lock-in circuit is established as follows: from one side of the power line by wire 334, wires 332, 340, 342, 344, contacts 306 and 308, wire 346, contacts 314 and 316, wire 348, contact 278, contact arm 282, wires 350 and 329, relay coil 266, and by wires 327 and 326 back to the other side of the line.

The relay remains closed and the motor runs to drive shaft 60 and rotate form roll 156 (clockwise as shown in FIGS. 3 and 8) to advance the stock as much as de sired. At this point, if it is desired to stop the motor, push-button 302 is momentarily actuated to open its contacts. This breaks the lock-in circuit and deenergizes the relay 266.

A bending operation is now to be performed, and pushbutton 16 is actuated. By this, the motor 254 and the air-valve 28 are energized simultaneously, as follows: Relay 266 (and thus the motor by its connections through the relay contacts) is energized from one side of the power line by wire 326, the relay coil, wire 328, wire 352, contacts 290 and 288, wires 354, 356', 340, 332, and 334 back to the other side of the power line. The relay 264 is energized from one side of the power line by wires 358 and 360, the coil of the relay, wires 362, 364 and 366, contacts 286 and 284, wires 368,. 356, 340, 332, and 334 back to the other side of the line. When relay 264 is energized, valve 28 is energized from the power line via wire 358, contact arm 272, contact 268, wire 359, the valve, and wire 361.

The lock-in circuit for relay 264 is now established by connection from one side of the line by wires 334, 332, 340, 342 and 370, contacts 310 and 312, wire 372, contacts 318 and 320, wire 374, contact 270, contact arrn 274, wires 376 and 3622, relay coil 264, and wires 360 and 358 back to the other side of the line. The lock-in circuit for relay 266 is established by connection from one side of the line by wires 334, 332, 340, 342 and 344, contacts 306 and 308, wire 346, contacts 314 and 316, wire 348, contact 278, contact arm 282, wires 350 and 329, relay coil, and wires 327 and 326 back to the other side of the line.

The motor now runs and continues to run, and air valve 28 admits air into cylinder 24 to pull the piston rod 230 to the right, and thus rotate arm 90. At this point, it is important to notice that the arm 9%} is moved clockwise to impart a bend while at the same time the form rolls 114, 144 and 156 are rotating in a direction to move the stock through the forming head. This simultaneous motion, it is believed, is the reason why the advantage of being able to bend thin-wall tubing without collapse of the tubing or wall wrinkling, is obtained.

It is to be noted, also, that at any point of the operation, either or both of motor (and thus the rotation of shaft 60 and the forming rolls) and the motion of arm 96, may be stoppedthe one independently of the other.

For example, if the bend shown in FIG. 8 has the desired radius of curvature, arm 90 may be stopped by means of cross-arm 224, and the motor operation continued to coil the tubing into a helix. Or, if it is desired to have the shown bend followed by a straight portion of the stock, the air-valve is deenergized by pushing pushbutton 364 to break the lock-in circuit to relay 264. Thereafter, spring 242 retracts arm 96 to the initial (fullline) position shown in FIG. 3, in which position the rotation of the form rolls will feed stock through the head without bending it for the desired length. Thereafter, the air-valve may be again actuated by means of push-button to swing arm 90* clockwise to impart a further bend in the stock. Furthermore, in between these operations of arm 90, the cross arm 224 may be adjusted to another position to give a bend of different radius of curvature.

Instead of first feeding straight stock through the head as described above in the first instance, the stock can be inserted as shown in FIG. 3, and push-button 16 actuated to start the motor 253 and arm 90 at the same time. This manner of operation will result in the stock being bent up to its starting end, as shown in FIG. 8, Without wall collapse or wrinkling.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As many changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings, shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. A machine for bending lengths of stock into arcuate shapes comprising a base; a shaft supported for rotation on said base; a first form roll having gear teeth and mounted on said shaft for rotation thereby; a support arm mounted on said base; a shaft stud mounted on said arm; a second form roll having gear teeth and mounted on said stud with its gear teeth meshing with the gear teeth of said first form roll, a portion of the face of said second form roll being spaced apart from "an opposing portion of the face of said first form roll to permit the engagement there between of said stock; a rotatable housing having an axis common with the axis of said shaft and surrounding the latter; a third form roll having gear teeth and mounted on said housing with its gear teeth meshing with the gear teeth of said first form roll, a portion of the face of said third form roll being spaced apart from an opposing portion of the face of said first form roll to permit the engagement there between of said stock; said rotatable housing normally being positioned so that said second and third form rolls are juxtaposed to each other; the opposing portions of the faces of said first and second form rolls defining together with the opposing portions of the faces of said first and third form rolls, when said housing is in said normal position portions of the boundary of a substantially straight passageway through which substantially straight stock may pass, and defining portions of the boundary of a curved passageway through which only curved stock can pass through said machine, when said housing and said third form roll have been rotated away from said normal position to a second position wherein said third form roll is substantially spaced from said second form roll; said having and said third form roll being adapted to be moved automatically from said normal position to said second position progressively while said first, second and third form rolls move stock through said machine.

2. The machine of claim 1, including first means for rotating said shaft, separate second means for rotating said housing and thus said third form roll about said shaft, means for controlling said first means alone, means for controlling said second means alone, and means for controlling jointly said first and second means.

3. The machine of claim 1, including means for rotating said housing comprising an air cylinder; a sprocketwheel axially mounted on said housing; a tension spring mounted by one end thereof on said base; a sprocket chain having one end thereof attached to the other end of said spring, the other end of said chain being attached to the movable end of the piston-rod of said cylinder, and said chain passing around and engaging said sprocket-wheel; said piston-rod upon actuation of said air-cylinder pulling on said sprocket chain against the tension of said spring when said air-cylinder is actuated, and readily adjustable means for limiting the stroke of said piston-rod thereby determining the amount of rotation of said housing.

4. A machine for bending lengths of stock into arcuate shapes comprising a base, a first form roll rotatably mounted on said base, a second form roll rotatably mounted on said base with its axis parallel to the axis of said first form roll, the peripheral edges of said first and second form rolls being in closely adjacent relation, means drivingly interconnecting said first and second form rolls whereby rotation of the former causes rotation of the latter, support means on said base adapted to rotate about the axis of said first form roll, a third form roll rotatably mounted on said support means with its axis parallel to the axis of said first form roll, the peripheral edges of said third and first form rolls being in closely adjacent relation, means drivingly connecting said first and third form rolls whereby rotation of theformer causes rotation of the latter, said support means normally being positioned so that said second and third form rolls are juxtaposed to each other, first drive means. connected with and for rotating said support means relative to said base so that said third form roll carried on said support means moves away from said second form roll and around said first form roll in planetary fashion, and seconddrive means connected with and for rotating said first form roll.

5. The machine of claim 4, said first drive means comprising a cylinder and piston, and readily adjustable means for limiting the stroke of said piston thereby determining the amount of rotation of said support means.

6. The machine of claim 4 including first means for controlling said first drive means alone, second, means for controlling said second drive means alone, and third means for controlling jointly said first and second drive means.

7. A machine for bending lengths of stock into arcuate shapes comprising a base; a shaft supported for rotation on said base; a first form roll mounted-on said shaft for rotation thereby and having a gear coupled for rotation therewith; a support arm mounted on said base; a shaft stud mounted on said arm; a second form roll mounted on said stud, and having a gear coupled for rotation with said second form roll, a portion of the face of said second form roll being spaced apart from an opposing portion of the face of said first form roll to permit the engagement therebetween of said stock; rotatable support means having an axis common with the axis of said shaft; a third form roll mounted on said support means and having a gear coupled for rotation with said third form roll, at least certain of said gears being drivingly interconnected, a portion of the face of said third form roll beingspaced apart from an opposing portion of the face of said first form roll to permit the engagement therebetween of said stock; said rotatable support means normally being positioned so that said second and third form rolls are juxtaposed to each other; the opposing portions of the faces of said first and second form rolls defining together with the opposing portions of the faces of said first and third form rolls, when said support means is in said normal position, portions of the boundary of a substantially straight passageway through which substantially straight stock may pass, and defining portions of the boundary of a curved passageway through which only curved stock can pass trough said machine, when said support means and said third form roll have been rotated from said normal position to a second position; said support means and said third form roll being movable from said normal position to said second position progressively while said form .rolls move stock through said machine.

8. A machine according to claim 7 wherein the second and third form rolls and their respective gears are 10 relatively smaller in diameter than said first form roll and its respective gear so that said second and third form rolls have a greater surface speed than said first form roll.

References Cited in the file of this patent UNITED STATES PATENTS 1,068,078 Replogle July 22, 1913 2,179,389 Turner Nov. 7, 1939 2,306,223 Parker Dec. 22, 1942 2,312,122 Parker Feb. 23, 1943 2,349,828 Moray May 30, 1944 2,501,241 Shaw Mar. 21, 1950 FOREIGN PATENTS 360,319 Great Britain Nov. 5, 1931 342,653 France July 13, 1904 

